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freebsd/eBones/des/cfb_enc.c
Geoff Rehmet 60643d379b Initial import of eBones.
(Including all changes for FreeBSD - importing the original eBones distribution
would be too complex at this stage, since I don't have access to Piero's 
CVS.)
(If you want to include eBones in your system, don't forget to include
MAKE_EBONES in /etc/make.conf.)
(This stuff is now also suppable from braae.ru.ac.za.)

Bones originally from MIT SIPB.
Original port to FreeBSD 1.x  by Piero Serini.
Moved to FreeBSD 2.0 by Doug Rabson and Geoff Rehmet.
Nice bug fixes from Doug Rabson.
1994-09-30 14:50:09 +00:00

111 lines
2.2 KiB
C

/* cfb_enc.c */
/* Copyright (C) 1993 Eric Young - see README for more details */
/*-
* $Id: cfb_enc.c,v 1.2 1994/07/19 19:21:48 g89r4222 Exp $
*/
#include "des_locl.h"
/* The input and output are loaded in multiples of 8 bits.
* What this means is that if you hame numbits=12 and length=2
* the first 12 bits will be retrieved from the first byte and half
* the second. The second 12 bits will come from the 3rd and half the 4th
* byte.
*/
int des_cfb_encrypt(in,out,numbits,length,schedule,ivec,encrypt)
unsigned char *in,*out;
int numbits;
long length;
des_key_schedule schedule;
des_cblock *ivec;
int encrypt;
{
register unsigned long d0,d1,v0,v1,n=(numbits+7)/8;
register unsigned long mask0,mask1;
register long l=length;
register int num=numbits;
unsigned long ti[2],to[2];
unsigned char *iv;
if (num > 64) return(0);
if (num > 32)
{
mask0=0xffffffff;
if (num == 64)
mask1=mask0;
else
mask1=(1L<<(num-32))-1;
}
else
{
if (num == 32)
mask0=0xffffffff;
else
mask0=(1L<<num)-1;
mask1=0x00000000;
}
iv=(unsigned char *)ivec;
c2l(iv,v0);
c2l(iv,v1);
if (encrypt)
{
while (l-- > 0)
{
ti[0]=v0;
ti[1]=v1;
des_encrypt((unsigned long *)ti,(unsigned long *)to,
schedule,DES_ENCRYPT);
c2ln(in,d0,d1,n);
in+=n;
d0=(d0^to[0])&mask0;
d1=(d1^to[1])&mask1;
l2cn(d0,d1,out,n);
out+=n;
if (num > 32)
{
v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffff;
v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffff;
}
else
{
v0=((v0>>num)|(v1<<(32-num)))&0xffffffff;
v1=((v1>>num)|(d0<<(32-num)))&0xffffffff;
}
}
}
else
{
while (l-- > 0)
{
ti[0]=v0;
ti[1]=v1;
des_encrypt((unsigned long *)ti,(unsigned long *)to,
schedule,DES_ENCRYPT);
c2ln(in,d0,d1,n);
in+=n;
if (num > 32)
{
v0=((v1>>(num-32))|(d0<<(64-num)))&0xffffffff;
v1=((d0>>(num-32))|(d1<<(64-num)))&0xffffffff;
}
else
{
v0=((v0>>num)|(v1<<(32-num)))&0xffffffff;
v1=((v1>>num)|(d0<<(32-num)))&0xffffffff;
}
d0=(d0^to[0])&mask0;
d1=(d1^to[1])&mask1;
l2cn(d0,d1,out,n);
out+=n;
}
}
iv=(unsigned char *)ivec;
l2c(v0,iv);
l2c(v1,iv);
v0=v1=d0=d1=ti[0]=ti[1]=to[0]=to[1]=0;
return(0);
}